Field of the Invention
The present invention relates to an image forming apparatus. Further, the present invention relates to an image forming system.
The image forming apparatus is generally configured to form an image on a recording medium. The image forming apparatus is, for example, an electrophotographic copying machine, an electrophotographic printer (e.g., a laser beam printer or a light emitting diode (LED) printer), or a facsimile apparatus, which can form an image through electrophotographic image forming processes. In general, the image forming apparatus is associated with a cartridge that is attachable to or detachable from an apparatus body thereof.
Description of the Related Art
There is a conventional developing device the maintenance for which is wholly performed by a service engineer of an office equipment supplier that has installed an electrophotographic image forming apparatus. On the other hand, a cartridge type is employable to enable each user to attach and detach the developing device to and from the electrophotographic image forming apparatus body. The cartridge type is useful in that the operability can be improved extremely because a user can perform the maintenance for the apparatus without relying on any service engineer. Therefore, the above-mentioned cartridge type has been widely employed for various electrophotographic image forming apparatuses.
The electrophotographic image forming apparatus includes a main body side engaging portion provided in the apparatus body to transmit a rotational force to a rotary member (e.g., an electrophotographic photosensitive drum or a developer carrier).
Further, a configuration for causing a coupling member provided on a process cartridge to engage with the main body side engaging portion to transmit the rotational force is conventionally known.
The above-mentioned coupling member, which is capable of serving as a rotational force transmission unit, can be configured to incline from a rotation axis of an electrophotographic photosensitive drum unit. According to such a conventionally known configuration, an engagement operation or a disengagement operation of the coupling member can be realized in the process of attaching or detaching the process cartridge to or from the apparatus body. The above-mentioned configurations are discussed in Japanese Patent No. 4498407, Japanese Patent Application Laid-Open No. 2014-98935, and Japanese Patent Application Laid-Open No. 2014-112169.
According to the configuration discussed in Japanese Patent No. 4498407, a coupling member can incline from a drum flange member serving as a rotational force transmitted member in a state where these members are connected to each other. More specifically, the coupling member is configured to have a bevel shape and an axial member provided on the drum flange member is configured to receive the coupling member in such a way as to enable the coupling member to incline relative to the drum flange member.
Further, according to the configuration discussed in Japanese Patent Application Laid-Open No. 2014-98935, a coupling member includes a spherical portion that serves as an inclination center. When the spherical portion is assembled with an accommodating portion provided in a drum flange member, the coupling member can be connected to the drum flange member so that the coupling member can incline relative to the drum flange member.
The spherical portion of the coupling member includes a protrusion that can transmit a rotational driving force to the drum flange member. The drum flange member includes an aperture having a diameter smaller than that of the spherical portion. The spherical portion can be brought into contact with an inner periphery of the aperture. Thus, it is feasible to hinder the coupling member from separating from the drum flange member. However, according to the above-mentioned configuration, it is necessary to design the accommodating portion carefully to prevent the inner periphery of the aperture from colliding with the protrusion of the spherical portion, and to incline the coupling member sufficiently. Therefore, the accommodating portion of the drum flange member tends to become greater.
In view of the foregoing, the configuration discussed in Japanese Patent Application Laid-Open No. 2014-112169 is characterized by causing a pin member to enter a through-hole of the spherical portion of the coupling member, instead of using the protrusion having the above-mentioned configuration. Further, the pin member is fixed to the drum flange member in such a way as to enable the coupling member to incline. According to the above-mentioned configuration, the pin member does not contact with the accommodating portion when the coupling member inclines, because the pin member is fixed to the drum flange member. On the other hand, the total number of parts increases because of the pin member, which is newly added to the coupling member and the drum flange member. Further, it is necessary to provide a sufficient clearance between the coupling member and the pin member. Therefore, the assembling work is rather complicated because it is necessary to hold both of the coupling member and the pin member when the coupling member and the pin member are assembled to the drum flange member.